Cambodia has a hot and humid tropical climate. The country is dominated by the wet southwest monsoon from May to October and the dry northeast monsoon from November to April. Most of the rain falls in the southwestern hilly area and the coastline facing the Gulf of Siam. The central lower areas are somewhat drier but hotter. Temperatures are between 23 C and 26 C at night, and 30 C to 35 C during the day most of the year, but April sees temperatures of 40 C occasionally. September and October are the wettest months. The country experiences the heaviest precipitation from September to October with the driest period occurring from January to February. Disastrous flooding occurred in 2001 and again in 2002, with some degree of flooding almost every year.